Fungicidal agents



United States Patent: O

The present invention relates to known diaryl azo compounds which have a remarkable high fungicidal activity.

It has been found that the diaryl azo compounds of the formula .\'x--.\=N--Xt--o n (I) in which R and R stand for alkyl, aralkyl and aryl,

3,152,033 Patented Oct. 6, 1964 "Ice and R taken together with the nitrogen atom preferably stand for heterocyclic radicals with 5-6 ring members such as pyrolidyl and morpholinyl. R further stands for hydrogen. X and X preferably stand for phenylene which may be substituted by chlorine, bromine, the nitrogen group, alkyl radicals with 1-4 carbon atoms, phenyl, alkoxy radicals with 1-4 carbon atoms, the hydroxy group and/ or the carboxy group.

In comparison with the coupling products of basic-substituted aromatic diazonium salts with compounds containing reactive methylene groups, known from the Belgian patent specification No. 594,503 and proposed for the same purpose, the agents according to the present invention exhibit a likewise substantially smaller toxicity to warm blooded creatures and a better tolerance by plants. The azo compounds, also known as fungicidally effective, in which R and R, (see the above mentioned formula) stand for hydrogen atoms, are much surpassed by the preparations to be employed according to the present invention in application against leaf fungi, as is apparent from the following table:

T able I ACTIVITY AGAINST PIIYTOPIIIIIORA INFESTANS ON TO MATOES Degree of infestation .altcr applica tion of the preparation in an active Preparation agent concentration of- N0. Constitution 0.025 0.006125 0.003125 percent pcrccnt percent- 1 II:I\' N=N-3: -on 100 100 100 2 (c In) N=t\' on 6 12 30 ll, s up; g I=N -01; run 100 up C l I;

| MMN-N:X/ --on s as ('1 H; s new N=X( o1r 100 100 we t; (Clfg)gr f N::. T OII 0 2 1 I R and R taken together with the nitrogen atom stand for heterocyclic radicals,

R further stands for hydrogen and X and X stand for arylene which may be substituted by halogen, nitro, alkyl, aryl, alkoxy, hydroxy, carboxy and/or carbalkoxy exhibit a high fungicidal activity.

The diaryl azo compounds of the invention are especially suitable for combating obnoxious fungi on green plant parts. On the other hand, the products show only a slight toxicity to warm blooded creatures as well as a slight phytotoxicity.

1n the above mentioned Formula I R and R preferably stand for all-:yl with 1-4 carbon atoms and phenyl. R

CH3 136 g. (1 mol) of 4-aminodimethyl aniline are di- 3 azotised at to C. in a mixture of 1000 cc. of water and 225 g. of concentrated hydrochloric acid with 70 g. of sodium nitrite, dissolved in 250 com. water. The diazonium salt solution is then allowed to flow into a soluextended as sprays or dusts. Other fungicides. insecticides, acaricides, wetting and adhesive agents or other substances favourably influencing the action of the preparations, can be added.

tion of 120 g. of resorcinol in 1200 cc. of water. After 5 The following examples illustrate the invention in more completion of the addition, the mixture is treated while detail. stirring vigorously with solid sodium bicarbonate until EXAMPLEI I t i gives an alkaline leactlon the dark preclpltae .iormed Test of the fungicidal activity in application against is further stirred for several hours, filtered off with suc- Ph to hthom infem v on tomatoes fter 20 hours standing of the mixture thoroughly y p t d d d tsot 60 C 4NN Young tomato plants (Bonny Best) are sprayed with 5 a en i g aqueous suspensions or emulsions of the preparations dllmct y f f g g 'j s z Z s at about mentioned below. When the sprayed coatings have dried. ga fi 1 a we we c p g the plants are inoculated in a moist chamber with an I i manner the followin com ounds to be aqueous slurry of fungus spores and these are then incuu g a is: accordin to the i g can be bated at 18 to 20 C. and 100% relative atmospheric t glc g humidity for 5 days. Evaluation follows of the degree of mm infestation by determination of the intensity of infestation 4-N,N-dimethylamino-4'-hydroxyazohen2ene on each feather-leaf. From the infestation frequency and 4-N,N-dimethylamino-3'-methyl-4'-hydroxyazobenzene infestation intensity, the degree of infestation is calculated 4 N,N-dimethylamino-3,5-dimethyl-4-hydroxyazoben- 20 and expressed in percent of the infestion of untreated conzene trols. whose degree of infestation is taken as 100. 4-N,N-dimethylamino-3'-phenyl-4'-hydroxy-azobenzene The values found are assembled in the following 4-N,N-dimethylamino-3'-chloro-4'-hydroxy-azobenzene Table II.

Table II Fungicitlal action against Pliyfopltlhum iuft'slnux on tomatoes; degree of infesta- Linn after ttmflittii-iofl at the Preparation Physical Properties M citing Point, C. preparation in active agent;

' concentration of 0.025 0.00025 0.00315 percent percent percent;

(CH;)zN- N=N@OH Brown erysta1stromxylenc. 191191(deeomp.) 6 12 (CH3)7N N:NAOH Red crystals from benzene 167168(decon1p.) 5 26 36 E (CH )z-N- IN=N-0II Brown crystals from ethanol.. 149 (l 2 13 (CH Z\ -N=N-@OII Red crystals from benzene 13S (deeoinp) 4 H? (ClI )z-N \-N=N- OII Brown crystals from ethanoL... 203 (deco1np.) 0 4 17 v (CHQ -A- t=N OH Brown crystals from t0luene 152-153 3 6 27 Comparison agent (Zine ethylene-bis-dithio carbamate) Control (untreated) The compounds to be used according to the invention are either applied as such or preferably in the usual way We claim:

1. Method for controlling fungi which comprises applying to said fungi an effective amount of a diaryl azo eompound of the formula 5 in which R is a member selected from the group consisting of hydrogen, alkyl with 1-4 carbon atoms and phenyl;

R is a member selected from the group consisting of alkyl with 1-4 carbon atoms and phenyl;

R and R when defined as alkyl and, taken together with nitrogen further stand for a 5-6 membered heterocyclic group; and,

X and X stand for a member selected from the group consisting of phenylene and substitution products thereof containing at least one member selected from the group consisting of chloro, bromo, nitro, alkyl with 1-4 carbon atoms, phenyl, alkoxy With 1-4 carbon atoms, hydroxy and carboxy.

2. Method for controlling fungi which comprises applying to said fungi an effective amount of 4-N,N-dimethylamino-3-methyl-4-hydroxyazobenzene.

3. method for controlling fungi which comprises applying to said fungi an effective amount of 4-N,N-dimethylamino-3'-methyl-4'-hydroxyazobenzene.

4. Method for controlling fungi which comprises applying to said fungi an effective amount of 4-N,N-dirnetl1- ylamino-3',5-dimethyl-4-hydroxyazobenzene.

5. Method for controlling fungi which comprises applying to said fungi an effective amount of 4-N,N-dimethylamino-3'-phenyl-4-hydroxyazobenzene.

6. Method for controlling fungi which comprises applying to said fungi an effective amount of 4-N,N-dimethylamino-2',4-dihydroxyazobenzene.

7. Method for controlling fungi which comprises apply ing to said fungi an effective amount of 4-N,N-dimethylamino 3-chloro-4'-hydroxyazobenzene.

8. Method for controlling fungi which comprises applying to said fungi an eflective amount of 4-N,N-dimethylamino-4'-hydroxy azobenzene.

9. Method for controlling fungi which comprises applying to fungi an effective amount of 4-pyrrolidyl-2',4'-dihydroxy-azobenzene.

10. Method for controlling fungi which comprises applying to said fungi an effective amount of 4-morpholyl- 2',4'-dimethyl-4-hydroxy azobenzene.

References Cited in the file of this patent UNITED STATES PATENTS 1,680,108 Ostromislensky Aug. 7, i928 2,010,512 Ebert Aug. 6, 1935 2,085,037 Mietzsch et al June 29, 1937 2,148,705 Mietzsch et a] Feb. 28, 1939 2,911,336 Urbschat et al Nov. 3, 1959 

1. METHOD FOR CONTROLLING FUNGI WHICH COMPRISES APPLYING TO SAID FUNGI AN EFFECTIVE AMOUNT OF A DIARYL AZO COMPOUND OF THE FORMULA 